KR987001072A - Optical Device Comprising a Plurality of Units Having at Least Two Geometrically-Differentiated Tapered Optical Waveguides Therein - Google Patents

Abstract

The present invention (a) a substrate; And (b) a plurality of units disposed on the substrate; It includes. Each unit consists of a plurality of inclined waveguides, each waveguide (i) having a light incidence surface adjacent to the substrate (a) and a light emitting surface spaced apart from the light incidence surface and the light incidence surface area being Larger than the light emitting surface area; (ii) inclined from the light incident surface to the light emitting surface to the light emitting surface; And (iii) at least one of the light incident surface area or the light emitting surface area of the at least one inclined waveguide is different from the corresponding surface area of the inclined waveguide remaining in the unit. Preferably the optical device is a viewing film. The viewing film of the present invention reduces or substantially eliminates brightness hot spots and interference patterns. The viewing film of the present invention is used in a wide range of applications, including, for example, computer terminals, display devices for air cockpits, automotive instrument panels, televisions and other devices that provide document, graphic or video information.

Description

Optical Device Comprising a Plurality of Units Having at Least Two Geometrically-Differentiated Tapered Optical Waveguides Therein

Optical waveguides, also known in the art as light transmissive devices or lightguides, are applied to display autonomy, such as projection displays, off-screen displays and direct view displays. Typically an optical element having a plurality of optical waveguides is used. See, for example, US Pat. Nos. 3,218,924 and 3,279,314 to Brandley, Jr. US Patent No. 4,767,186 to et al. Such displays are used in a wide range of applications, including computer terminals, air cockpit displays, automotive raised panel televisions, and other devices that provide document, graphic, or video information.

The known display device has the following problems. Depending on the exact optical waveguide geometry, known display devices may produce non-monotonically decreasing light output luminosity as the viewing angle varies from perpendicular to the optical device and parallel to the optical device. will be. 10 shows the minimum amount occurring in such a light distribution output pattern. The observer will detect peaks between these lowest values in the light distribution output pattern as intensity hot-spots, which will obviously be disadvantageous for recognizing uniformly diverging optical devices.

Another problem that occurs with known display devices is the formation of interference patterns between Moire and its foil. A typical liquid crystal display device comprises a first substrate having a first polarizer element, an appealing electrode on top and a matrix circuit portion for applying voltage to these pixel electrodes, a second substrate having a liquid crystal layer, a mattress layer with openings and Has a second polarizer element. The pixel is formed by an opening on the second substrate and a pixel electrode formed on the first substrate. When the optical device is assembled with such a liquid crystal display device, moir and other interference patterns often occur because the critical dimension for the pixel pitch separation line width is similar or almost equal to the critical dimension for the engineering device. Seeing these patterns is never what you want.

Another problem caused by known display devices is that it is difficult to obtain very specific light emission distributions in only one type of optical waveguide present in the optical device. Since the light emission distribution is uniquely defined by the waveguide, the waveguide must therefore be specially designed to exactly conform to the needs of the user.

Accordingly, there is a need in the art for optical devices in which the occurrence of intensity spots and moir and other interference patterns are reduced or nearly eliminated to produce more uniformly diverging optical devices.

The present invention relates to an optical device comprising a plurality of units having inclined engineering waveguides differentiated into at least two geometries.

1 is a schematic diagram showing an inclined optical waveguide having a rectangular or square base useful in the present invention, FIG. 2 is a schematic diagram showing an inclined optical waveguide element having a circular base useful in the present invention, and FIG. 3 is an inclined optical waveguide. FIG. 4 shows a side view of a unit of two inclined optical waveguide elements having different light emitting surface areas and the same light incident surface area, FIG. Perspective view of a unit of two different inclined optical waveguide elements of FIG. 4, FIG. 6 is a side view of a unit of two inclined optical waveguide elements having different light incidence area and light emitting surface area, and FIG. Schematic design of a lithographic phototool used to photolithically construct 16 different optical waveguides as a unit, FIG. 8 shows different light incident surface areas 14a and 14b and a light emitting surface area 16 a-16b) illustrates one possible arrangement of the inclined optical waveguide element in another unit 26, FIG. 9 shows the inclined optical waveguide element used in Example 1 having a square emission surface area of 25 microns on one side. 10 is a graph showing the light distribution results of the square optical waveguide element used in Example 1 having a square emission surface area of 10 microns on one surface. Figure 11 is a plan view of a unit 26 of four different optical waveguide elements, in which case the incident surface region 14 and the emitting surface region 16 are noted in each case (a)-(e). The continuity illustrates how unit 26 can be produced taking into account the combination of two different emitting surface areas 16a and 16b. Fig. 12 is a graph showing the result distribution obtained by combining the inclined optical waveguide elements shown in Fig. 11 (c), and Fig. 13 shows the result distribution obtained by combining the inclined optical waveguide elements shown in Fig. 11 (d). Fig. 14 is a graph showing the result distribution obtained by combining the inclined optical waveguide elements shown in Fig. 11E, and Fig. 15 is a schematic plan view of the resultant optical device of Example 2;

* Description of the major symbols in the drawings

12... Tapered waveguides 26. Unit

14... Light input surface

16... Light output surface

18... Sidewall 20... Taper angle

28... Hot spot

The present invention is explained in more detail based on the following examples.

The inventors have developed an optical device that meets the above needs in the art. The optical device comprises (a) an engine; And (b) a plurality of units on said engine; It includes. Each of the units consists of a plurality of inclined waveguides, (i) each of the waveguides has a light incidence surface adjacent to the trachea (a) and a light emitting surface spaced apart from the light incidence surface, An area is larger than that of the light emitting surface; (ii) each waveguide is inclined from the light incident surface to the light emitting surface; And (iii) at least one of the light incident surface area or the light emitting surface area of at least one of the inclined waveguides is different from the corresponding surface bottom of the inclined waveguide remaining in the unit.

When used as a viewing film, the optical device of the present invention is particularly advantageous. Since at least one of the light incident surface area and the light emitting surface area in at least one inclined waveguide is different from the corresponding surface area of the inclined waveguide remaining in the unit, the occurrence of intensity hot spots and moir and interference patterns is reduced or Substantially eliminated. As a result, the viewing film is provided with a display device that emits more uniformly. In addition, with a waveguide combination inclined within the unit, a very specific emission distribution can be chosen to be obtained through the coupling effect of the waveguide so that it does not need to be due to a single waveguide configuration.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in Figs. 1 and 2, the inclined waveguide 12 degrees has an angular light incident surface 14, a light emitting surface 16 and a side wall 18. As shown in Figs. For each inclined waveguide 12, the area of the light incident surface 14 is larger than that of the light emitting surface 16. FIG. The cross section of the waveguide 12 inclined in a plane parallel to the substrate plane can have any shape, including circles, squares, hexagons, ellipses and rectangles. 1 shows a tilted waveguide 12 having a rectangular cross section. 2 shows a drawn waveguide 12 having a circular cross section. The shape of the sidewall 18 may be straight or curved.

If the waveguide 12 is inclined such that the area of the light emitting surface 16 is smaller than the area of the light incident surface 14, the angular distribution of light emitted from the light emitting surface 16 will be larger than the angular distribution of light incident on the light incident surface 14 . When an optical film having a plurality of inclined waveguides 12 is used with the display device, it will change the angular distribution of the emitted light from the modulating means so that the image can be viewed from the modulating means at a larger angle. The area of the light emitting surface 16 of each inclined waveguide 12 is preferably about 1-50% of the area of the light incident surface 14, more preferably about 3-25% of the area of the light incident surface, and most preferably It is about 4-12% of the area of the light incident surface.

In order for the display device having the viewing film of the present invention to have high overall and throughput, the total area of the entire waveguide light incident surface is preferably about 40% or more, more preferably about 60, based on the total substrate area of the viewing film. At least%, and most preferably at least about 80%. One inclined waveguide 12 having a light incident surface 14, a light emitting surface 16 and a straight sidewall 18 is shown in FIG. 3. Extending the inclined straight sidewall 18 until they intersect forms an inclination angle 20. The value of the inclination angle 20 is preferably in the range of about 2-14 °, more preferably about 4-12 ° and most preferably about 6-10 °.

Inclined waveguide 12 has a height of 22. The dimension 24 is the minimum transverse distance across the waveguide light incident face 14. For example, if light incident surface 14 is square, dimension 24 is the length of one surface of the square. As another example, if light incident surface 14 is rectangular in shape, dimension 24 is the smaller of the two sides of the rectangle. The specific value for dimension 24 can vary widely depending on the center-to-center distance between adjacent pixels of the modulation means. In order not to degrade the resolution of the image formed by the modulating means, the dimension 24 should be less than or equal to the center-to-center distance between adjacent pixels of the modulating means. For example, if the center-to-center distance between adjacent pixels in the modulation means is 200 microns, dimension 24 is preferably about 5-200 microns, more preferably about 15-200 microns and most preferably about 25-. 100 microns.

After dimension 24 is selected, height 22 can be specified by height 22 relative to dimension 24. The ratio of the height 22 to the dimension 24 can vary widely depending on how much desired to increase the angular distribution of light emitted from the light emitting surface 16 relative to the angular distribution of light incident on the light incident surface 14. The ratio of height 22 to dimension 24 is preferably about 0.25-20, more preferably about 1-8, and most preferably about 2-6.

At least one of the light incident surface area 14 or the light emitting surface area 16 of the at least one inclined waveguide 12 in each unit differs from the corresponding light incident surface area or the light emitting surface area in the unit. As used herein, the term "different" is about 2% of the light incident surface area or light emitting area corresponding to at least one of the light incident surface area or the light emitting surface area of the at least one inclined waveguide corresponding to the inclined waveguide remaining in the unit. It means that there is a difference. For example, if the light incident surface area in one inclined waveguide is x, each light incident surface area in the inclined waveguide remaining in the unit is 1.02x or more or 0.98x or less. In another embodiment, if the light emitting surface area in one inclined waveguide is y, each of the light emitting surface areas in the inclined waveguide remaining in the unit is not less than 1.02y or not more than 0.98y. At least one of the light incident surface area or the light emitting surface distant in the at least one inclined waveguide is preferably at least about 5% more than the light incident surface area or the light emitting surface area corresponding to the inclined waveguide remaining in the unit. The preferences vary by at least about 10%, most preferably at least about 20%.

Thus, the other surface area includes: (1) at least one light incident surface area of at least one inclined waveguide differs from each light incident surface area of the inclined waveguide remaining in the unit, and (2) at least one At least one light emitting surface area of the inclined waveguide is different from each ball emitting surface area of the inclined waveguide remaining in the unit, and (3) both the light incident surface area and the light emitting surface area of the at least one inclined waveguide are It is different from the light incident surface area and the light emitting surface area of the inclined waveguide remaining in the unit.

4 shows a side view of a unit 26 comprising a plurality of inclined waveguides 12 having different light exit surface areas 16 and having the same light incident surface area 14 and the same height 22. 5 is a perspective view of unit 26 of FIG. 4. FIG. 6 is a side view of the unit 26 including a plurality of inclined waveguides having different light incident surface areas 14 and having different light emitting surface areas 16 and the same height 22.

Preferably at least two inclined waveguides 12 in the unit differ in at least one of the corresponding light incident surface area or light emitting surface area and light incident surface area 14 or light emitting surface area 16 of the inclined waveguide remaining in the same unit. More preferably, the light incident surface area 14 or the light emitting surface area 16 is different from each other. Most preferably, each inclined waveguide 12 in the unit has at least one of the corresponding light incident surface area or four light emitting surface area and the light incident surface area 14 or light emitting surface area 16 of all other inclined waveguides in the same unit. It is different.

The inclined waveguide 12 may have various shapes, including but not limited to rectangular, square, circular, elliptical and hexagonal. Within unit 25, the inclined waveguide 12 may be of the same shape or of a different shape, although not shown. For example, one inclined waveguide 12 of unit 26 chiller may have a rectangular cross section, while the other inclined waveguide 12 may have a circular cross section. Most preferably, the inclined waveguide 12 is selected to maximize the fill factor by dividing the light incident surface area by the unit area. Other types of cross sections of inclined waveguides in the unit may be:

Each inclined waveguide in unit 26 is preferably of a different shape of the inclined waveguide in the same unit.

Although US Pat. No. 4,605,283 teaches that the same ribs parallel to one another may have any desired shape and may or may not be all the same shape, such teachings have been made by those skilled in the art. It is not possible to infer the present invention.

Inclined waveguide 12 is a transparent solid polymer material having a refractive index of about 1.45-about 1.65 and may be commercially available polymethylmethacrylate, poly (4-methylpentene), polycarbonate, polyester, polystyrene and acrylate or And polymers formed by photopolymerizing methacrylate monomers. The inclined waveguide comprises a polymer formed by copolymerizing two essential or methacrylate monomers. The inclined waveguide is preferably made of a photopolymerizable material comprising two essential components. The first essential component is a hyperpolymerizable monomer, in particular an ethylenically unsaturated monomer, which will give a transparent solid polymeric material. More preferred materials have a refractive index of about 1.50-1.60 and are urethane acrylates or urethane methacrylates, ester acrylates or ester methacrylates, epoxy acrylates or epogit methacrylates, poly (ethylene glycol) acryl And polymers formed by photopolymerizing an acrylate or methacrylate monomer mixture composed of an organic monomer containing a rate or poly (ethylene glycol) methacrylate or a vinyl-containing organic monomer. It is preferable to use the monomer mixture in the photopolymerizable mixture to control the crosslink density, viscosity, adhesion, curing rate and refractive index and to reduce the discoloration, cracking and peeling properties of the photopolymer formed from the composition.

Examples of useful more preferred monomers include methyl methacrylate; n-butyl acrylate (BA); 2-ethylhexyl acrylate (EHA); Isodecyl acrylate; 2-hydroxyethyl acrylate; 2-hydroxypropyl acrylate; Cyclohexyl acrylate (cha); 1,4-butanediol diacrylate; Ethoxylated bisphenol A diacrylate; Neopentyl glycol diacrylate (npgda); Diethylene glycol diacrylate (DEGED); Diethylene glycol dimethacrylate (PEGDMA); 1,6-hexanediol diacrylate (HDDA); Trimethylol propane triacrylate (TMPTA); Pentaerythritol triacrylate (PETA); Pentaerythritol tetra-acrylate (PETTA); Phenoxyethyl acrylate (PEA); β-carboxyethyl acrylate (β-CEA); Isobornyl acrylate (IBOA); Tetrahydrofurfuryl acrylate (THFFA); Propylene glycol monoacrylate (MPPGA); 2- (2-methoxyethoxy) ethyl acrylate (EOEOEA); N-vinyl pyrrolidone (NVP); 1,6 hexanediol dimethacrylate (HDDMA); Triethylene glycol diacrylate (TTEGDA) or tetraethylene glycol dimethacrylate (TTGDMA); Tetraethylene glycol diacrylate (TTEGDA) or tetraethylene glycol dimethacrylate (TTEGDMA); Polyethylene glycol diacrylate (PEGDA) or polyethylene glycol dimethacrylate (PEGDMA); Dipropylene glycol diacrylate (DPGDA); Tripropylene glycol diacrylate (TPGDA); Ethoxylated neopentyl glycol diacrylate (NPEOGDA); Tripropylene glycol diacrylate (TPGDA); Ethoxylated neopentyl glycol diacrylate (NPEOGDA); Propoxylated neopentyl glycol diacrylate (NPPOGDA); Aliphatic diacrylate (ADA); Alkoxylated aliphatic diacrylate (AADA); Aliphatic carbonate diacrylate (ACDA); Trimethyl wool propane trimethacrylate (TMPTMA); Ethoxylated trimethylolpropane triacrylate (TMPEOTA); Propoxylated trimethylolpropane triacrylate (TMPPOTA); Glyceryl propoxylated triacrylate (GPTA); Tris (2-hydroxyethyl) isocyanurate triacrylate (THEICTA); Dipentaerythritol pentaacrylate (DPEPA); Ditrimethylolpropane tetraacrylate (DTMPTTA); And alkoxylated tetraacrylate (ATTA); It includes.

Particularly useful are mixtures in which at least one monomer is a multifunctional monomer, such as diacrylate or triacrylate, to produce a crosslinked network structure in the reacted photopolymer. Most preferred materials for use in the present invention are crosslinked polymers formed by photopolymerizing a mixture of ethoxylated bisphenol A diacrylate and trimethyl propane triacrylate. The refractive index of the most preferred material is about 1.53-1.56. The refractive index of the transparent solid material does not necessarily need to be uniform throughout the entire waveguide element. It is desirable to have materials with non-uniform refractive indexes, such as streaks or scattering particles or domains, because the nonuniformity further enhances the emission of light from the waveguide output.

The amount of monomer in the photopolymerizable material can vary widely. The amount of monomer or the total amount of the monomer mixture is usually about 60-99.8%, preferably about 80-99% by weight, most preferably about 85-99% by weight of the photopolymerizable material.

As another essential component, the polymerizable material includes a photoinitiator that is activated by actinic radiation to produce an activated species that causes photopolymerization of the monomers. The system of clarifiers typically extends spectral functions into domains with spectral utility, in the vicinity of the ultraviolet region and in the visible spectral region, for example, where the laser is excited and penetrating many conventional optical materials. Sensitizer. Usually, the photoinitiator is a free radical-generating addition polymerization initiator activated by actinic light and is preferably thermally inactive at room temperature and below (eg about 20-25 ° C.).

Examples of such initiators are disclosed in US Pat. No. 4,943,112 and references cited therein. Preferred free radical initiators include 1-hydroxy-cyclohexyl-phenyl ketone (irgacure 184); Benzoin; Benzoin ethyl ether; Benzoyl isopropyl ether; Benzophene; Benzidimethyl ketal (grgacure 651); α, α-dimethyloxy-α-hydroxy acetophenone (Darocur 1173); 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-propane-1-one (Darocur 2959); 2-methyl-1- [4-methylthiophenyl] -2-morpholino-propan-1-one (Irgacure 907); 2-benzyl-2-dimethyl-amino-1- (4-morpholinophenyl) -butan-1-one (Irgacure 369); Poly {1- [4- (1-methylvinyl) phenyl] -2-hydroxy-2-methyl-propan-1-one} (Esacure KIP); [4- (4-methylphenylthio) -phenyl] phenylmethanone (Quantacure BMS); Dicamperquinone; And 50% 1-hydroxycyclohexyl phenyl ketone and 50% benzophenone (Irgacure 500); to be.

More preferred open reagents are benzidimethyl ketal (Irgacure 651); α, α-dimethyloxy-α-hydroxy acetophenone (Darocur 1173); 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184); 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-propane-1-one (Darocur 2959); 2-methyl-1-4- (methylthio) phenyl] -2-morpholino-propan-1-one (Irgacure 907); 2-benzyl-2-dimethylamino-1-4 (morpholinophenyl) butan-1-one (Irgacure 369); And 50% 1-hydroxycyclohexyl phenyl ketone and 50% benzophenone (Irgacure 500); It includes. The most preferred photoinitiator does not yellow upon irradiation and therefore does not increase the coloration of the composition with a Gardner grade of 8 or higher as measured by ASTM D 1544-80 upon exposure to 190 ° C. for 24 hours. The photoinitiator is benzyl dimethyl ketal (Irgacure 184); 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-propan-1-one (Darocur 2959); And 50% 1-hydroxy cyclohexyl phenyl ketone and 50% benzophenone (Irgacure 500); Include.

The amount of photoinitiator that must be present to gradient substantially to collimation across the photopolymerizable mixture system is about 0.1-12% by weight based on the total weight of the photopolymerizable material. The amount of photoinitiator is preferably about 0.5-12% by weight, and more preferably about 0.5-8% by weight based on the total weight of the photopolymerizable material. Preferred gradients are influenced not only by the concentration of the initiator, but also by the choice of irradiation wavelength present in the source of exposure, which can be controlled by one skilled in the art.

In addition to the essential components, the photopolymerizable material may include various optional components such as stabilizers, inhibitors, plasticizers, optical brighteners, mold release agents, chain transfer agents, other photopolymerizable monomers, and the like.

The photopolymerizable material is thermally aged in air at 190 ° C. for 24 hours as defined in ASTM D 4538-90A and then causes deterioration of characteristics such as cracking and peeling or after yellowing (as measured by ASTM D 1544-80). It is desirable to include a stabilizer to prevent or reduce coloration on the Garder color Scale. Such stabilizers include UV absorbers, light stabilizers and antioxidants.

UV absorbers include 2- [2-hydroxy-3,5-di (1,1-dimethylbenzyl) phenyl] -2-H-benzo (Tinuvin 900); Poly (oxy-1,2-ethanediyl, α- (3- (3- (2H-benzotriazol-2-yl) -5 (1,1-dimethylethyl) -4-hydroxyphenyl) -1 Hydroxyphenyl such as oxopropyl-ω-hydroxy (Tinvin1130) and 2- [2-hydroxy-3,5-di (1,1-dimethylpropyl) phenyl] -2H-benzotriazole (Tinuvin 238) Benzotriazoles and hydroxybenzophenones such as 4-methoxy-2-hydroxybenzophenone and 4-n-octoxy-2-hydroxybenzophenone. , 2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidylyl ) Sebacate (Tinuvin 770); Bis (1,2,2,6,6-pentamethyl-4-piperidinyl) Sebacate (Tinuvin 292); Bis 1,2,2,6,6-pentamethyl- Hindered amines such as -4-piperidinyl) -2-n-butyl-2- (3,5, di-tert-butyl-4-hydroxy-pyrosybenzyl) malonate (Tinuvin 144); and N-β-hydroxy-ethyl-2,2,6,6-tetramethyl-4-hydroxy-piperi Polyesters of succinic acid with (Tinuvin 622.) Antioxidants include 1,3,5-trimethyl 2,4,6-tris 3,5-di-tertbutyl) -4-hydroxybenzyl) benzene, 1,1,30tris- (2-methyl-4-hydroxy-5-tert-butyl) phenyl) butane, 4,4'-butylidene-bis- (6-tert-butyl-3-methyl) phenol , Tris- (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, cetyl-3,5-tris- (tert-butyl-3-hydroxy-2,6-dimethylbenzyl) (Cyasorb 1790); Stearyl-3-3,5-diert-butyl-4-hydroxyphenyl) proprionate (Irganox 1076); Pentaerythritol tetrabis (3,5, di-tert-butyl-4-hydroxyphenyl) (Irganox 1010); And thiodiethylene-bis (3,5-di-tert-butyl-4-hydroxy) hydro cinnamate (Irganox 1035); It includes.

Preferred stabilizers used in the present invention are antioxidants. Preferred antioxidants are 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl) -hydroxybenzyl) benzene, 1,1,3-tris- (2-methyl- 4-hydroxy-5-tert-butylphenyl) butane, 4,4'-butyllitene-bis- (6-tert-butyl-3-methyl) phenol, 4,4'-thiobis- (6-tert -Butyl-3-methyl) phenol, tris- (3,5-tert-butyl-4-hydroxybenzyl) isocyanurate, cetyl-3,5-di-tert-butyl-4-hydroxybenzene (Cyasorb Substituted phenols such as UV 2908; 3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076); Pentaerythritol tetrabis (3,5-di-tert-butyl-4-hydroxyphenyl) (Irganox 1010); And thiodiethylene-bis- (3,5-di-tert-butyl-4-hydroxy) hydrocinnamate (Irganox 1035); And stearyl-3- (3,5di-tert-butyl-4-hydroxyphenyl) proprionate (Irganox 1076); It includes.

The amount of stabilizer in the composition can vary widely and is usually about 0.1-10% by weight based on the weight of the photopolymerizable material. Preferably about 0.1-5% by weight based on the weight of the photopolymerizable material, and more preferably about 0.2-3% by weight based on the weight of the photopolymerizable material.

In order to produce the viewing film of the present invention, the inclined waveguide 12 may be manufactured on a substrate. Inclined waveguide 12 can be manufactured by a variety of techniques, including injection molding, extrusion, hot rolling casting, and photopolymerization processes. Inclined waveguide 12 is formed by ultraviolet irradiation of a layer of photopolymerizable material through a pattern mask, as described in US Application No. 08 / 148,749, filed November 8, 1993. The substrate is placed on top of a layer of photopolymerizable material, which is in turn placed on top of a bottom support plate having a release layer.

The mask has a pattern of opaque regions that allows ultraviolet light to only transmit through the region of the required pattern of the inclined waveguide. Ultraviolet rays from mercury or xenon lamps are directed directly to the surface of the mask. Ultraviolet light passing through the transparent area of the mask causes the photopolymerization reaction of the mask in the exposed area of the photopolymerization layer directly below the transparent image area of the mask. Photopolymerization does not occur in the region of the photopolymerization shielded from ultraviolet rays by the opaque region of the mask. After irradiation with ultraviolet light, both the mask and the bottom support plate with the release layer are removed. The unreacted monomer is washed with a suitable solvent such as acetone, methanol or isopropanol, leaving a pattern of photopolymerization sites on the substrate. The photopolymerization site corresponds to the array in the inclined waveguide according to the present invention.

In order for the inclined waveguide 12 to have an appropriate shape, the light absorption of the photopolymerizable layer that has not reacted at the ultraviolet wavelength must be large enough so that a gradient of ultraviolet intensity is formed through the coating during exposure to ultraviolet light. That is, the amount of ultraviolet light available to initiate the photoreaction in the monomer layer will be reduced from the top or image mask face towards the bottom or bottom support tube face due to the limited absorption of the monomer layer. This inclination of the ultraviolet light causes the amount of photopolymerization reaction from the top to the bottom to be inclined, resulting in a unique inclined structure of the improved waveguide structure, a geometrical structure that is easily accessible by the method of the present invention.

The gradient of photopolymerization occurring from the top to the bottom of the film may further be affected by the presence of dissolved oxygen gas in the photopolymerizable layer, where oxygen is absorbed by the free radicals generated in the photopolymerization process. Except that it acts to reduce or eliminate the photopolymerization reaction. The action of such dissolved oxygen gas on the photopolymerization process is well known to those skilled in the art. Moreover, the essential geometry of the photopolymer can be further influenced by the self-focussing process. That is, since the light irradiated to the surface of the monomer layer initiates copolymerization at the surface and the refractive index of the solidified polymer material is larger than that of the liquid monomer, it serves to refract the light transmitted therethrough. In this way the aerial image of light irradiated onto the monomer closer to the bottom of the monomer layer changes through refraction by the already-polymerized material on top. This effect can narrow the resulting polymerized structure from the top face to which the blaze light is directed towards the bottom or side of the support plate of the caterpillar.

The refractive index of the gap region between the inclined waveguides should be smaller than that of the inclined waveguide. Preferred materials for the gap region include air having a refractive index of 1.00, fluoropolymer materials having a refractive index of about 1.30-1.40, and silicone materials having a refractive index of about 1.40-1.44. Most preferred materials are air and fluorinated laurylurethane.

In a preferred embodiment of the present invention, the gap region between the inclined waveguides also includes a light absorbing material such as, for example, a light absorbing black particulate material. By using a light absorbing material in the gap, the viewing film of the present invention provides greater contrast and reflects less ambient light to the viewer. To minimize the area of black material in contact with the side of the inclined waveguide, absorbing particles are used in the gap region rather than the continuous black material. The use of continuous black material in the gap region reduces the light-absorbing absorption loss for light transmitted through the waveguide through internally absorbed and broken internal reflection mechanisms. The light absorbing component is preferably maintained at least about 1 micron, and preferably at least 3 microns on the side of the waveguide. Any absorbing material can be used for particle formation. Examples of absorbing black particulate materials that can be used include carbon lampblack powders, mixtures of carbon black and toner, and mixtures of carbon black and fluoropolymers. The absorbing black particulate matter causes the array to exhibit a dark matte black, good light transmission, and little surface refraction (reflection or scattering) when viewed from the observer side of the display device.

The total number of inclined waveguides 12 in each unit 26 is most preferably at least two. The viewing film has a plurality of units 26 on the substrate and the total number of units 26 depends on the final size required by the viewing film. In the case of limitation, each unit has the same area as the entire display area and each waveguide is statistically different.

In a given conventional manufacturing method, the pattern of light and dark areas on the mask allows the freedom to choose the shape, size and direction of the light incident area 14 of the viewing screen. FIG. 7 illustrates a plan view of a lithographic phototool used to photographically define sixteen different inclined optical waveguides as repeat unit 26 of an optical element. The thick and thick lines represent the darker portions of the photomask that define the incident light surface region 14 during lithography. Example 2 will describe the results using this phototool. Inclined waveguide 12 may be fabricated on any substrate. At the minimum, the substrate transmits light within a wavelength range of about 400-700 mm and these visible wavelength ranges are the most preferred ranges in which the optical waveguides to be formed operate. In addition, the engine more preferably transmits within a range of about 250-400 mm as a region where many useful photoinitiators absorb ultraviolet rays. Alternatively, if it is necessary to use the viewing film of the present invention in the vicinity of the infrared range, about 700-200 mm, it will also be preferable to use a transparent substrate in this range. The refractive index of the substrate will be about 1.45-1.65. Most preferred refractive index is about 1.50-1.60.

Preferred substrate materials are commercially available and include transparent polymers, glass and fumed silica. Useful transparent polymers include poly (ethylene terephthalate) and poly (ethylene terephthalate glycol), polyacrylates and polymethacrylates, polystyrenes and polycarbonates. Properties required by these materials include mechanical and optical stability at typical operating temperatures of display devices. Compared to glass, the transparent polymer adds the advantage of structural flexibility, which can form the product into large pieces and then cut and laminate as needed. Preferred materials for the substrate are glass and polyesters such as polyethylene terephthalate. The thickness of the substrate can vary widely. Preferably the thickness of the substrate is about 0.5 mil (0.0005 inch or 12 microns) -10 mil (0.01 inch or 250 microns). Inclined waveguide 12 may also be manufactured directly on the planar element.

FIG. 8 shows a first possible arrangement of inclined optical waveguide elements different in light incident surface areas 14a and 14b and different light emitting areas 16a-16d in unit 26. In this case the unit contains twelve inclined optical waveguide elements. Eight of these elements contain the same rectangular light incident surface area 14b. Of these eight elements, four comprise a narrow rectangular emitting light surface area 16a and four comprising a wide rectangular emitting light surface area 16b. The remaining four elements comprise the same square light incident surface area 14a. Of these four elements, two comprise a narrow square emitting light surface area 16c and the other two comprising a large square emitting light surface area 16d. By mixing the rectangular and square elements, the resulting unit will have a dominant emitted light distribution with light distributed in the direction perpendicular to the long axis of the rectangle. 8 shows that any combination of elements can be combined within the unit. The choice of the unit is to adjust the distribution of light to meet the needs of the user.

Examples of adhesives useful for the adhesive layer include pressure sensitive adhesives such as ethylene-based adhesives and vinyl acetate adhesives; Thermosetting adhesives such as epoxy, urethane and silicone; And photopolymerizable adhesives such as acrylates, methacrylates and urethanes, and mixtures thereof. If the substrate is glass, then adhesion is achieved by changing the glass surface to 3- (trimethoxysilyl) propyl methacrylate; 3-acryloxypropyl trichlorosilane: and trimethylsilylpropyl methacrylate; It can be suitably promoted by reacting with a specific type of silane compound including. If the substrate is polyethylene terephthalate (PET), adhesion can be facilitated by using an adhesive treated PET film such as Hostaphan 4500 (Hoechst-Celanese). If the substrate was coated with an emulsion, adhesion can be facilitated by 3-acryloxypropyltrichlorosilane (Huls America A0396).

The protective layer is used over the emitting end of the inclined waveguide 12 to prevent mechanical damage to the emitting surface of the inclined waveguide and also to trap the absorbing particulate material in the gaps between the inclined waveguides. The protective layer may be injection molded or laminated overcoat. The protective layer may also be applied to the emitting surface of the inclined waveguide 12 before filling the gap region with the absorbing black particulate material. The protective layer consists of a transparent backing material, such as the material used to form the support layer, and an anti-reflective film, optionally and preferably formed from a material, such as magnesium fluoride, so that from the surface of the inclined waveguide 12 Reduce the spectral refraction of the ambient light. The anti-reflection coating can also be evaporated directly at the light emitting end and the gap region of the inclined waveguide. Useful anti-reflective coatings can also be evaporated directly at the light emitting end and the gap region of the inclined waveguide. Useful anti-reflective coatings include US Pat. No. 5,061,769 to Aharoni et al .; 5,118,579; 5,139,879 and 5,178,955; It is the fluoropolymer being taught.

The viewing film of the present invention can be used in the direct view flat panel display of U.S. Patent No. 86,414, filed August 26, 1994. The polarizer and the resulting display device are used in computer terminals, televisions, display devices for air cockpits, automotive instrument clusters and other devices that provide document, graphic or video information. Moreover, the viewing film of the present invention is an optical property of road signs, cathode ray tube (CRT) displays, deadfront displays and other information display means, such as documents, graphic or video information, which do not fall within the scope of flat display devices. It can be used to change or improve the brightness, or to change or improve the brightness or optical properties of the lighting system.

1. Two sloped waveguide geometries were modeled and then mathematically combined into unit 26 to include other optical elements. The two waveguides were the same in height but different in emitting surface area. For all geometries, both the light incident surface and the light emitting surface were square. The non-imaging optical properties of the inclined waveguide can be modeled using a non-sequential ray tracing computer program. FIG. 9 shows the emission distribution of a particular inclined waveguide with 10000 rays randomly distributed over the incidence plane region and disorderly distributed at an incidence angle of −10 to + 10 °. The modeled inclined waveguide had a 45 micron square light incident surface area on one side, a square light emitting surface area 25 microns on one side, a height of 125 microns, and a straight sidewall and an inclination angle of 4.6 °. The light emitting surface area was 31% of the light incident surface area. Arrow 30 in FIG. 10 corresponds to the maximum relative luminous intensity of the emission fraction. Arrow 28 corresponds to the intensity of the hot spot taken away from the main central peak as the luminosity distance from the first minimum to the first maximum of the emission distribution. By obtaining the ratio of hot spot intensity 28 to the maximum light intensity 30, a value for relative hot spot intensity can be obtained and the emission distributions from different inclined optical waveguides are compared.

FIG. 10 shows the emission distribution in another inclined waveguide assuming that 10000 rays are randomly distributed in the light incidence plane region from -1 to + 10 °. The modeled beveled waveguide had a square light incident surface area of 45 microns on one side, a square light emitting surface area of 10 microns on one side, a height of 125 microns, a straight sidewall and an inclination angle of 8 °. The light emitting surface area was 5% of the light incident surface area.

11 shows a plan view of unit 26 of four different optical waveguide elements. In each of (a)-(e), the incident surface region 14 and the emitting surface region 16 are noted. The subsequent figures show a possible way of generating unit 26 taking into account a combination of two different emitting surface areas 16a and 16b. In this embodiment, the incident light area 14 of all four inclined optical waveguides was kept constant. The emission distribution from FIG. 9 corresponds to a unit of the optical waveguide element as shown in FIG. 11A. Similarly, the emission distribution in FIG. 10 corresponds to the unit of the optical waveguide element in the unit shown in FIG. 11B; The release distribution in FIG. 12 corresponds to the unit shown in FIG. 11C; The emission distribution in FIG. 13 corresponds to the unit shown in FIG. 11D; And the emission distribution in FIG. 14 corresponded to the unit shown in FIG. 11E. By sequentially considering each of the combinations of inclined optical waveguides having two different emitted light surface areas, proceeding with this figure illustrates that an effective emitted light distribution can be applied at the request of the consumer. In particular, in this embodiment, the overall width at the half maximum of the light emission distribution has been changed by only combining with other numbers of inclined optical waveguide elements having a wide and narrow light emission distribution. Furthermore, the magnitude of the relative hot spot intensity taken as the ratio of hot spot intensity 28 to the maximum brightness 30 shows that it changes from one combination to the next. In conclusion, one can choose the combination of emission distribution and hot spot intensity that best suits a given application.

2. An array of 16 different inclined optical waveguides was prepared by the method described above. The phototool used in the manufacturing process had hexagons with different dimensions collected together to produce the unit cell array. Dimensions on the phototool and the resulting optical waveguide The dimensions on the incident light plane ranged from 35-60 microns. The geometry was mainly square or nearly square.

Optical microscopic examination was performed about the light incident surface and the emitting surface of the resultant optical device. From these microscopic examinations, the planar tissue spherical shape of the resultant optical device was measured and plotted. It is noted in FIG. 15 that the length of unit 26 is 200 microns. Light incidence plane 14 represents the space in dark lines between the incidence planes of the inclined optical waveguide elements, on average 10 microns. The dashed line represents the emitted light surface area 16. The gap region was filled with light absorbing black particulate matter. The emitted light distribution of the resulting optical device was evaluated by directly irradiating the collimated helium-neon laser beam vertically into the light incident plane region 14. The emission distribution has been shown to have unique combinatorial effects as expected from an optical device consisting of one type of inclined optical waveguide.

Thus, the viewing film of the present invention reduces or substantially eliminates brightness hot spots and interference patterns, for example, computer clear, display panels for cockpits, automotive display panels, televisions and documents, graphics or It is used in a wide range of applications, including other devices that provide video information.

Claims (12)

(a) a substrate; And (b) a plurality of units disposed on the substrate, each unit comprising a plurality of tapered waveguides, each waveguide comprising (i) a light incident surface adjacent to the substrate (a); Having a light emitting surface spaced apart from said light incident surface, said light incident surface area being larger than said light emitting surface area and (ii) inclined from said light incident surface to a light emitting surface; And (iii) at least one light incident surface area or at least one light emitting surface area of the at least one inclined waveguide is different from the corresponding surface area of the inclined waveguide remaining in the unit; Optics The optical device according to claim 1, wherein the total number of the inclined waveguides in each unit is about 2 or more. The method of claim 1, wherein at least two inclined waveguides in each unit have one or more light incident surface areas or light emitting surface areas different from the corresponding surface area of the inclined waveguides remaining in the unit. Optics The optical device according to claim 1, wherein each inclined waveguide in the unit has at least one light incident surface area or a light emitting surface area different from the corresponding surface area of each of the inclined waveguides remaining in the unit. The optical system of claim 1, wherein at least one of the light incident surface area or the light emitting surface area of the at least one inclined waveguide is at least about 5% different from the corresponding surface area of the inclined waveguide remaining in the unit. Device The optical device of claim 1, wherein at least one of the light incident surface area or the light emitting surface area of the at least one inclined waveguide is at least about 20% different from the corresponding surface area of the waveguide remaining in the unit. The optical device of claim 1, wherein at least one inclined waveguide in the unit has a different light incidence surface area compared to the light incidence surface area of all inclined waveguides remaining in the unit. The light emitting surface area of claim 1, wherein the at least one inclined waveguide in the unit has a different light incidence surface area and a light emitting surface area as compared to the light incidence and light emitting surface areas of all inclined waveguides remaining in the unit. Optical device characterized in that (a) a substrate; And (b) a plurality of units disposed on the substrate, each of which comprises a plurality of inclined waveguides; Wherein each waveguide has (i) a light incidence surface adjacent to the substrate (a) and a light emitting surface spaced apart from the light incidence surface, the light incidence surface area being greater than the light emitting surface area (ii) ) Inclined from the light incident surface to the light emitting surface; And (iii) at least one of the light incident surface area or the light emitting surface area of at least one of the inclined waveguides is different from the surface area corresponding to the inclined waveguides remaining in the unit; Viewing film 17. The viewing film of claim 16, wherein the total number of inclined waveguides in each unit is two or more. 17. The view of claim 16, wherein at least one of the light incident surface area or the light emitting surface area of the at least one sloped waveguide differs by at least about 5% from the surface area corresponding to the sloped waveguide remaining in the unit. 17. The viewing film of claim 16, wherein the light incident surface area or the light emitting surface area of the at least one sloped waveguide is different from the corresponding surface area of all sloped waveguides remaining in the unit. ※ Note: The disclosure is based on the initial application.